Successful outcome in a case of idiopathic multicentric Castleman disease with atypical lymphadenopathy and kidney injury: Diagnostic challenges and treatment approach-Case report.

Idiopathic multicentric Castleman disease is a rare and complex disease characterized by systemic inflammation, lymphadenopathy, and multiorgan involvement. This case report presents a 66-year-old Chinese man with idiopathic multicenter Castleman disease without significant lymphadenopathy and challenging diagnosis. Patients present with fever, fatigue, loss of appetite, weight loss, and acute kidney injury. Initially, a urinary tract infection was suspected, but despite anti-infective treatment, the patient's symptoms persisted. Lymph node biopsy, although there is no significant lymphadenopathy, confirms idiopathic multicenter Castleman disease. Treatment includes thalidomide, cyclophosphamide, and dexamethasone, as well as supportive measures and infection control. After 8 months of follow-up, the patient's clinical symptoms, inflammatory markers and renal function were significantly improved, and there was no symptomatic recurrence. This case underscores the importance of considering idiopathic multicenter Castleman's disease in patients with persistent fever and systemic inflammation, even in the absence of significant lymphadenopathy. Early identification and accurate diagnosis of idiopathic multicenter Castleman's disease can lead to the initiation of targeted therapy strategies that ultimately yield favorable outcomes.